Quick reversing capacitor motor



w. w; WARNER 2,407,117

QUICK REVE RSING CAPACITOR MOTOR Filed Feb. 26, 1945 Sept. 3, 1946.

Inveritor Wilbur- W. Warner,

His. Attorney.

Patented Sept. 3, 1946 UNITED STATES New York PATENT OFFICE Wilbur W.Warner, Fort Wayne, Ind., assignor to General Electric Company, acorporation of Application February 26, 1945, Serial No. 579,708

Claims.

My invention relates to quick reversin capacitor start motors of thetype utilizing regenerative braking and plugging during the reversingoperation and employing a speed responsive switch, relay means, and areversing switch for the control thereof. Apparatus of this type isdescribed in a copending application Serial No. 521,516, filed February8, 1944, to Fred W. Suhr and myself, now Patent No. 2,380,270, July 10,1945, assigned to the same assignee as the present invention. In saidprior application the same relay was de pended upon to shift fromrunning to regenerative connections for both directions of motorrotation and as a result, the connections could be changed at a rate nofaster than the dropout action of such relay and necessitated a slightdelay in operating the reversing switch in order to prevent reenergizingthe motor from the line instead of establishing the reversingconnections. The present invention relates primarily to the use ofseparate relays for the different directions of rotation and theirconnections which permit of the instantaneous operation of the reversingswitch without danger of improper operation of the reversing control anda correspondingly quicker motor reversing action.

The features of my invention which are believed to be novel andpatentable will be pointed out in the claims appended hereto. For abetter understanding of my invention, reference i made in the followingdescription to the accompanying drawing in which Fig. 1 represents anembodiment of my invention employing a four-pole reversing and controlswitch. Fig. 2 is essentially the same as Fig. 1 except using athree-pole reversing and control switch. In Figs. 1 and 2 the reversingswitch is used as the motor line switch. Fig. 3 shows a modification ofthe invention using a two-pole reversing switch and a separate lineswitch, and in Fig. 4 a two-pole reversing control line switch is usedin conjunction with a motor having two main field windings separatelyemployed for the opposite directions of motor operation. In all casesseparate relays are used for the opposite directions of motor rotation,and the reversing switch is instantaneously reversible, and hence can bea snap action switch operated either automatically or manually.

The motor with which my invention is employed may have a squirrel cagerotor I, a main or running field winding 2, and a starting field winding3 in the circuit of which is a capacitance 4 for producing the desiredshift in phase of the fluxes of the two motor windings which are woundin quadrature axes. The starting winding circuit includes an automaticswitch 5 which may be operated by a speed responsive centrifugal device6 for opening the starting winding circuit after the motor has startedand reached a suitable speed so that the motor runs single phase on themain winding alone. At start the two winding circuits are energized inparallel from the source of supply I through the switch 8 which isrepresented in Fig. 1 as being a four-pole, double-throw switch with themovable switch blades omitted in order more clearly to show the terminalconnections.

The switch 8 is provided with connections to line terminals 1 and henceto the end of the start winding connected to the lower line terminal, tothe main winding 2 for energizing and reversing the same, to thestarting winding circuit through the coils of relays 9 and i0 and to themovable switch contacts I I and I2 of such relays. Relay 9 is energizedby the starting winding current when the switch 8 is closed to the leftand the speed responsiveswitch 5 is in the start position on contact 13as represented. It is noted that the position of the reversing switch 8selects the relay which is initially energized by the starting winding.current. Under these conditions the movable switch blade of relay H isin the upper position shown in Fig. 1 and completes the energizingcircuit of the main winding through the energizing coil of relay 9, andthe main winding running current thus holds the relay in energizedposition after the starting winding circuit is opened by movement of theswitch blade 5 to a running contact I l. The lower contacts shown at l5and I6 of the relays are both connected to the running contact M of thespeed responsive switch, and these connections are used for establishingregenerative braking circuits for the motor in the early part ofreversing operations. The significance of the connections will beevident from the following description of the operation for thedifferent directions of rotation.

To start the motor in a iven direction, say counterclockwise, the switch8 is closed to the left. This closes a circuit for the start windingfrom the lower line terminal 1, winding 3, condenser 4, speed responsiveswitch 5 on contact 13, relay coil 9 through the upper blade of switch 8to the upper line terminal '5. The current of the starting windingcircuit flowing through the selected relay coil ii causes its movablecontactor l l to rise to the upper stationary contact, whereupon acircuit for the main winding is established as follows: From lower lineterminal, the lower blade of switch ll, winding 2, the lower centerblade of switch 8, a connection ll, the upper center blade of switch 8,movable contact II of selected relay 9 in the upper position, coil ofrelay 9, upper blade of switch ii to the upper line terminal. The motorthus starts and comes up to speed, and the speed responsive switch 5moves to running contact 5 l, thereby opening the starting windingcircuit and connecting this end of the starting winding circuit tocontact I4. Relay 3 remains energized because of the main windingcurrent through its coil. No complete circuit is established throughcontact I4 and the speed responsive switch at this time and hence themotor runs single phase on winding 2 alone. The motor may be stoppedslowly by simply opening switch 8. To reverse quickly, switch 8 isthrown from closed position to the left to closed position to the right.This interrupts the main winding energizing circuit and establishes aclosed regenerative braking circuit through the main and start windingsand condenser traced as follows: From lower blade of switch 8, startwinding 3, condenser i. switch 5 on contact I l, lower contact I6 andmovable contact I2 of relay I6, upper center blade of switch 3,connection I1, lower center blade of switch 8, main windin 2, back tolower blade of switch 8. It will be noted that to establish thisregenerative braking circuit, the switch 8 may be reversedinstantaneously or as fast as it is possible to do so with any kind ofswitch including an electronic switch, and does not depend upon thedropping out of relay 9, since the necessary regenerative brakingcircuit, except through switch 8, was already set up through contactorl2 resting on its lower contact I6, and contacts I4 and 5, the then idlestart winding 3 and capacitance 4. The motor thus quickly reduces speeduntil the speed responsive switch 5 returns to the starting contact I3.It will be noted that when switch 8 was reversed, the connectionsthereto from main winding 2 were also reversed; hence, when the speedresponsive switch moves to the start contact I3, the motor becomesconnected for the reverse direction of rotation as follows: From lowerline terminal, start winding I3, condenser 4, switch 5, contact I3, coilof relay H3, upper blade of switch 8 to the right to the upper lineterminal; relay I which is now selected by the position of the reversingswitch, pulls up and completes the main winding energizing circuit aspreviously described except that now switch 8 is closed to the right andrelay I0 instead of 9 is used. Since the motor is still runningcounterclockwise, it is plugged and quickly stops and reverses, andcomes up to speed in a clockwise direction. The speed responsive switchmoves to the running contact, cutting out the start winding, and themotor runs single phase on the main winding alone with its currentflowing through the coil of selected relay Iii, establishing aholding-in circuit for such relay. During the described reversingoperation the relay 9 has of course dropped out, and its movable contactis now in the lower position but .at no time during the reversingoperation does it establish any complete circuit but does partially setup or partially establish the regenerative braking circuit to becompleted and used when reversing from clockwise to counterclockwiseoporation, by throwing switch 8 from closed position at the right toclosed position at the left. The regenerative braking, lugging andstarting, when changing from clockwise to counterclockwise operation,are the same as above described except that switch 8 is thrown fromright to left and relay 8 is used instead of relay IE. While switch 8may be reversed instantaneously, which is very desirable in many cases,no difiiculty will arise by reason of slow operation of this switch, andby proper manipulation of switch 8 either the step of regenerativebraking, or plugging, or both steps, may be omitted.

Fig. 2 operates the same as Fig. 1. However, in Fig. 2 a three-poledouble-throw switch I8 is substituted for switch 8 of Fig. 1, theelimination of one switch blade made possible by a rearrangement of theswitch connections which are fully illustrated in Fig. 2.

In 3 I have represented an embodiment of my invention which may bedesirable in some cases because it uses a two-pole, double-throwreversing switch I9 and a separate energizing switch 20. With switchclosed for the desired direction of rotation, the motor is started byclosing switch 20. Switch I!) is used for reversing service and may bereversed instantaneously. When the motor is to be shut down, switch 20is opened. It will be noted that the connection from the startingcontact I3 of the speed responsive switch to the coils of relays 9 andIll is through similar resistances 2i and 22, resistance 2| in serieswith coil 9, and resistance 22 in series with coil I9; and such twoseries groups are connected in parallel in the starting winding circuit.As a result, when the motor is started, both relays pull up. The mainwinding circuit is thus closed through either contactor II or I2,depending upon the position of reversing switch I 9. For instance, withreversing switch it thrown to the left, the main winding is energizedthrough the upper blade of switch it and contactor I I of relay 9. Now,when the speed responsive switch 5 cperates and moves to running contactI l, relay IE! will drop out because with respect to the main Windingcurrent through contactor II, both resistances 2| and 22 are in serieswith the coil of relay I0, whereas neither is in series with the coil ofrelay 9. Hence, practically all of the main winding current flowsthrough the coil of relay 9 which thus holds in, whereas relay ill dropout and partially sets up the regenerative braking circuit preparatoryto the next reversing 0peration. Such regenerative braking circuit iscompleted when switch I9 is reversed or closed to the right and may betraced as follows: From crossconnection 23 of switch Iii, windingcondenser 4, switch 5, contact I4, contacts I6 and I2 of relay ID indeenergized position, lower blade of switch It closed to the right,winding 2 back to upper blade of switch I9 and cross-connection 23.

When running in the opposite direction, relay I 0 is held in by the mainwinding current, and the reversing regenerative braking will be throughthe lower contact I5 and movable contactor ll of relay 9. Thus theoperation is essentially the same as in Figs. 1 and 2. The resistances2i and 22 are relatively low in value and since they are in parallel inthe starting winding circuit during the short starting period, oiTer nodifnculty.

In Fig; 4 the operating results previously described are obtained by theuse of a combined line and reversing double-pole, double-throw switch 24and the use of a motor with two main. field windings 25 and 2B wound orconnected for opposite directions of motor operation in conjunction withthe relays 9 and it and their connections as illustrated. The motor isstarted by closing switch 24 in a direction determined the direction ofrotation desired. Assume the switch. 24 is closed to the left, relay 9is energized and pulls in and main winding 25 is thus energized whilerelay l remains deenergized to partially establish the regenerativebraking circuit which will use now idle main winding 26. When switch 24is now reversed, regenerative braking occurs by reason of circulation ofcurrent through the following circuit: lower blade of switch 24, winding3, condenser 4, switch on its running contact 14, lower contact andmovable contactor I?! of relay 90, main winding 26, back to the lowerblade of switch 24. As soon as the speed responsive switch moves to thestarting contact l3, plugging followed by starting in the oppositedirection is obtained, using main winding 26 energized through relay NJin the pulled-in position. In the meantime relay 9 has dropped outpreparatory to regenerative braking and will use main winding 25 whenswitch 24 is again thrown to the left to reverse the motor. The form ofthe invention of Fig. 4 may be useful where the load of the motor issomewhat diiierent for the opposite directions of rotation, which can betaken care of by suitable differences in the two main windings. Also,the switch 24 employed in Fig. 4 is of standard type readily availableand requires reduced space as compared to the other arrangements.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A quick reversing capacitor motor having displaced main and. startfield windings, capacitance in series with the start winding, anautomatic switch for opening the starting winding circuit when the motorcomes up to speed during a starting operation, said switch having arunning contact to which one end of the starting winding circuit thenbecomes connected, a pair of relays at least one of which is adapted tobe energized through the automatic switch during the starting operation,said relays both having a movable contact and stationary contacts forestablishing holding-in circuits for the relays when energized andconnection to said running contacts when deenergized, a double-throwreversing switch for reversing the motor by reversal of the main fieldof the motor, said switch establishing a connection to the other end ofthe starting winding circuit in both of its reversing positions, to themovable contact of one of said relays in one of its reversing positionsand to the movable contact of the other of said relays in its otherreversing position, energizing terminals for said motor so arranged thatthe energizing current for the main winding of the motor flows throughone or the other of said relays depending upon the position of thereversing switch, and constitutes the holding-in current of such relayand prevents it dropping out when the automatic switch opens thestarting winding circuit during a starting operation, said other relay(in deenergized position) and automatic switch (on its running contact)then partially establishing a regenerative braking circuit for the motorwherein the main and start motor windings and capacitance are connectedin series, which circuit is completed upon reversal of the reversingswitch.

2. A quick reversing capacitor motor having displaced main and startwindings, capacitance in series with the start winding, an automaticswitch for opening the starting winding circuit when the motor comes upto speed during a starting operation, said switch having a runningcontact to which one end of the starting winding circuit then becomesconnected, a pair of relays a selected one of which is energized throughthe automatic switch during the starting operation, said relays bothhaving a movable contact and stationary contacts for establishingholding-in circuits for the relays when energized and connections tosaid running contacts when deenergized, a double-throw reversing switchassociated with the main windings for reversing the motor, said switchestablishing a connection to the other end of the starting windingcircuit in both of its reversing positions, to the movable contact ofone of said relays in one of its reversing positions and to the movablecontact of the other of said relays in its other reversing position,energizing terminals for said motor and relays also connected throughsaid reversing switch and so arranged that the position of the reversingswitch selects the relay to be energized during a starting operation andthe energizing current for the main winding of the motor flows throughthe selected relay, and constitutes the holding-in current of such relayand prevents such relay from dropping out when the automatic switchopens the starting winding circuit during a starting operation, saidother relay (in deenergized position) and automatic switch (on itsrunning contact) then partially establishing a regenerative brakingcircuit for the motor wherein the main and start motor windings andcapacitance are connected in series, which circuit is completed uponreversal of the reversing switch.

3. A quick reversing capacitor motor having displaced main and startwindings, capacitance in series with the start winding, an automaticswitch for opening the starting winding circuit when the motor comes upto speed during the starting operation, said switch having a runningcontact to which one end of the starting winding circuit then becomesconnected, 2. pair of relays, a connection made by the automatic switchwhen in starting position to one energizing terminal of each relaythrough which a selected one of such relays is energized during thestarting operation, said relays both having a movable contact andstationary contacts for establishing holdingin circuits for the relayswhen energized and connections to said running contact when deenergized,a double-throw reversing switch associated with the main winding of themotor for reversing the motor and through which the motor and relays areenergized, said switch having connections to the other terminals of saidrelays arranged to select the relay to be energized through theautomatic switch during a starting operation depending upon the positionof the reversing switch, said reversing switch also establishingconnections to the other end of the starting winding circuit and to themovable contacts of the selected relay in the two reversing positions ofthe reversing switch such that energizing current for the main windingflows through the selected relay and constitutes the holding-in currentfor such relay during single phase operation, said other relay (indeenergized position) and the automatic switch (on its running contact)then partially establishing a regenerative braking circuit for the motorwherein the main and start motor windings and capacitance are connectedin series, which circuit is completed upon reversal of the reversingswitch.

4. A quick reversing capacitor motor having displaced main and startwindings, capacitance in series with the start winding, an automaticswitch for opening the starting winding circuit when the motor comes upto speed during a starting operation, said switch having a runningcontact to which one end of the starting winding circuit then becomesconnected, a pair of relays, an impedance connected between one pair ofenergizing terminals of said relay through which both relays areenergized in parallel through the automatic switch during the startingoperation, said relays both having a movable contact and stationarycontacts for establishing holding-in circuits for the relays whenenergized and connections to said running contacts when deenergized, adouble-throw reversing switch associated with the main windings forreversing the motor, said switch establishing a connection to the otherend of the starting winding circuit in both of its reversing positions,to the movable contact of one of said relays in one of its reversingpositions and to the movable contact of the other of said relays in itsother reversing position, a pair of energizing terminals for said motor,one terminal being connected to said reversing switch and to startwinding, a line switch between the other line terminal and the otherpair of energizing terminals of said relays whereby the energizingcurrent for the main winding of the motor flows through one or the otherof said relays depending upon the position of the reversing switch, andconstitutes the holding-in current of such relay, whereas the otherrelay drops out when the automatic switch opens the starting windingcircuit during a starting operation, said other relay (in deenergizedposition) and automatic switch (on its running contact) then partiallyestablishing a regenerative braking circuit for the motor wherein themain and start motor windings and capacitance are connected in series,which circuit is completed upon reversal of the reversing switch.

5. A quick reversing capacitor motor having first and second main fieldwindings and a displaced starting field winding, the first main windingbeing used for motor operation in a clockwise tive braking cii suit fordirection and regenerative braking in a counterclockwise direction andthe second main winding being used for motor operation in acounterclockwise direction and for regenerative braking in a clockwisedirection, a capacitance in series with the start winding, an automaticswitch for opening the starting winding circuit when the motor comes upto speed during a starting operation, said switch having a runningcontact to which one end of the start winding becomes connected when themotor is up to speed, a pair of relays, one or the other of which isselectively energized through the automatic switch during the startingoperation depending upon the position of a later mentioned reversingswitch, said relays both having a movable contact and stationarycontacts for establishing holding-in circuits for the relays whenenergized and connections to said running contact when deenergized, adouble-throw energizing and reversing switch for the motor, said switchhaving connections to energizing terminals and to the other end of thestarting winding circuit in both positions, a connection through onemain winding to the movable contact of one relay and an energizingconnection to such relay in one reversing position and through the othermain winding to the movable contact of the other relay and an energizingconnection to such other relay in the other reversing position wherebythe main winding energizing current becomes the holding-in current forthe selected relay to which such winding is connected depending upon theposition of the motor reversing switch, the energized relay andautomatic switch (on its running contact) then partially establishing aregenerathe motor in which the now idle windings of the motor andcapacitance are connected in series, which circuit is completed uponreversal of the reversing switch.

WILBUR W. WARNER.

